Abrading device for grinding-machines.



P. N. 11 F. E. GARDNER. ABRADING DEVICE FOR GRINDING MACHINES.

APPLICATION FILED SEPT. 8, 1911;

Patented 1101128, 1911 Q7@ jv/venian? EYQCZQZZ'C E GQ12252191 T fr'srarsrarrnn einen;

FREDERICK-N. GAEDNEE'iAN-li) EREDERIC E. GARDNER, 0F BELOI'I,llVISGt'JNSIItl",A

ASSGNOR @E @NE-TAHRD TO WMD@ THOMPSON, 0F BESLUIT, WIW

GONSIN.

esamina nnvrcr. ron calunnie-MACHINES.

antenne.

Speci'cation of Letters Eatent.

rat-enten new. ce, rear.

Application led September 6, 1911. -Serial No. 648,263.

l To'allwhofm 'it may concern.

Be it known that we, FREDERICK N. GARD- NER and FREDERIC E. GARDNER,citizens of the'United States, residing at Beloit, in y.the county ofRock and State of Wisconsin, have invented certain new andl usefulImprovements in Abrading Devices for Grinding- Machines, oLwhich thefollowing is a specification.

This invention relates to grinding machines of the type comprising adisk wheel provided with a removable abrading surface and commonlytermed disk grinders.

The abrading surface has usually4 consisted of a layer of granularabrasive material secured toa backing of paper. The backing with itsfacing of abradingv material constitute what is usually termed anabrasive disk. Th@ abrasive isk is secured to the disk wheel of thegrinding machine by means ofcement, and it is important that the cementbe Aof such character that the abrasive disk will be held tightly enoughfor operating purposes but not too tightly to be readily pulled fromthewheel when the abrasive disk is worn and mustibe replaced. `Whenvsuch cement, ,however1s used w1t-l1 abraslve` disks as heretoforeconstructed, the paper and the glueY that secures the abrasive materialto the paper, absorb moisture from the cement and swell or shrink,causing the yabrasive disk to wrinkle and to pull away from the wheelhere and there,` when the machine is left standing fora time or overnight. To overcome this diculty, glue and hard cement have been emplo'edto secure the abrasive disk to the dis wheel, but when such cementingmaterials are used more time is consumed in attaching the disk to thewheel, the wheel must be removed from the machine, a central opening ofconsiderable sizemust be provided in the abrasive disk to provide accessto the screws by means of which the wheel is secured to its spindle, andmuch diHiculty is encountered in removing the worn-out disk from thewheel. With vabrasive disks as heretofore constructed, swelling ofthepaper andthe glue has also been caused by absorption of moisture fromthe air'; furthermore, if the air was moist when the disk was applied tothe wheel and subsequently became drier,

the aper and glue shrank. y

e obviate these diiculties by Vmaking the paper backing of minimumthickness, by

waterproofing the rear side of the paper backing, and by embedding anetwork of" threads in the waterproong layer to compensate for theweakness of the thin pa er `being shown as provided with an abrasivedisk embodying our invention. Fig; 2 is a 'ragmental rear side view ofsaid abrasive dlsk. Flg. 3 is a fragment-al sectional view` oftheabrasive disk upon an enlarged scale. `In the drawings, 1 indicates4the spindle of a disk grinder, 2 a collar fixed uponv said spindle,and-3 a disk wheel,` secured tothe collar by means of screws 4.

5 is the abrasive disk.

5n indicates the cement that holds the disk 5 to the wheel 3, saidcement being of any suitable character, preferably Vone that is not verystrong.

The abrasive disk.5 consists of a layer of paper 6, and a facing ofgranular abrasive material 7, attached to the paper in any common orpreferred manner, as by means of glue, the rear side of thepapl-Kbacking 6 being waterproofed by means of a coatlngv 'the contrarythe abrading disk remains smooth and Hat. The network of threads 9imparts strength to the abrasive disk so that the latter can be pulledod the disk wheel without tearing or splitting. None of the cement isabsorbed by the waterproof layer and very little byV the threads, forwhich reason a cement coating of minimum thickness may be used and thetimenecessary to reface a wheel is thereby shortened, since a thin coatof cement becomes firm more qlllilickly than would a thick coat. The teads adhere strongly to the wheel, but the disk. The network of threadsprovides a multiplicity of attaching pointsbetween the wheel and theabrasive disk. v

The wheel 3` is subject to expansion and 4contraction due to change inthe temperature of the air, while the abrasive disk is liable toexpansion and contraction caused by variations in the amount of moisturein the air. The network of threads constitutes, in conjunction with thecement, an elastic connection between the paper-backed abra-sive 1a erand the wheel which ermits of such sllght chan es in the dimenslonsofthe wheel or the dis without causing the disk to buckle or break loosefrom its fastening.

We claim as our invention: .1. An abrasive disk for use with diskgrinders consisting of a paper disk, a waterproof coating upon one sideof the disk, a. layer of abrasive material upon .the other side of thedisk, and means attached to the rear side of the Waterproor` coating forimparting strength to the disk.

2. An abrasive disk for use upon disk grinders consisting of a paperdisk, a waterprooi:I coating upon one side of said disk,a

layer of abrasive material upon the other side 'of the disk, and a netWork of threads adherent to the waterproof coating, said networkproviding a multiplicity of attaching points,

the interstices between the threads ccnstituting depressions in thegeneral surface of the rear side of the disk.

' In testimony whereof we aix our signa- I

